CODEWITHSUNDEEP
iphoneobjective-ciosuialertview
Nikita P
Nikita P

Reputation: 4246

Exc_Bad_Access only sometimes on showing alert view

I have many threads calling the following function by performSeleactoreOnMainThread method:

-(void) showAlert: (NSString *)message{
if ([NSRunLoop currentRunLoop] != [NSRunLoop mainRunLoop]) {
    NSLog(@"<< perform in main thread>>");
    [self performSelectorOnMainThread:@selector(showAlert:) withObject:message waitUntilDone:NO];
}
UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Info" message:message delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
[alert show];
}

As, in any case, this method will be called only on main thread, I am not getting the reason for EXC_BAD_ACCESS crash on the line: [alert show]

And this crash comes only sometimes. Please help.

Upvotes: 1

Views: 377

Answers (4)

Paresh Navadiya
Paresh Navadiya

Reputation: 38259

Alternative Why don't u use this:

 [alert performSelectorOnMainThread:@selector(show) withObject:nil waitUntilDone:YES];

instead of

 [alert show];

Upvotes: 0

Levi
Levi

Reputation: 7343

Put a return at the end of the if block:

-(void) showAlert: (NSString *)message{
if ([NSRunLoop currentRunLoop] != [NSRunLoop mainRunLoop]) {
    NSLog(@"<< perform in main thread>>");
    [self performSelectorOnMainThread:@selector(showAlert:) withObject:message waitUntilDone:NO];
    return;
}
UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Info" message:message delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
[alert show];
}

Upvotes: 0

howanghk
howanghk

Reputation: 3090

I guess you forgot to add return; in your code so that your code below the if are also executed no matter it is in main loop or not.

a simple fix may be:

-(void) showAlert: (NSString *)message{
    if ([NSRunLoop currentRunLoop] != [NSRunLoop mainRunLoop]) {
        NSLog(@"<< perform in main thread>>");
        [self performSelectorOnMainThread:@selector(showAlert:) withObject:message waitUntilDone:NO];
        return;
    }
    UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Info" message:message delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
    [alert show];
}

Upvotes: 2

Midhun MP
Midhun MP

Reputation: 107231

Issue is due to whether the if condition is true or false the alertview displaying method will work. Change your method like:

-(void) showAlert: (NSString *)message
{
 if ([NSRunLoop currentRunLoop] != [NSRunLoop mainRunLoop])
 {
    NSLog(@"<< perform in main thread>>");
    [self performSelectorOnMainThread:@selector(showAlert:) withObject:message waitUntilDone:NO];
 }
 else
 {
   UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Info" message:message delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
  [alert show];
 }
}

Upvotes: 0

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